Installation for stabilizing the vehicle body against curve-tilting

ABSTRACT

An installation for stabilizing the vehicle body against curvetilting, in which an erecting force is exerted on the side of the vehicle body disposed on the outside of the curve, whereby a pressure medium is supplied in dependence on the curve drive of the vehicle directly to the pistons of cylinder-piston units connected between the wheels and the vehicle body in such a manner that the cylinder-piston unit associated with the wheel on the inside of the curve is shortened in the sense of a lowering of the vehicle body and the cylinder-piston unit associated with the wheel on the outside of the curve is lengthened in the sense of a lifting of the vehicle body.

Sites aim 1191 Enlce et a1.

[ 4] HNSTALLATHON FOR STABHJZING THE VEHICLE BODY AGAINST CURVE-THLTING[75] inventors: Kurt Enke, Kirchheim/Teck; Klaus Bauer,Stuttgart-Heumaden; U110 Saltlen, Waiblingen, all of Germany [73]Assignee: Daimler-Benz AG, Stuttgart,

. Germany [22] Filed: Sept. 28, 1971 [21] Appl. No.: 184,569

[30] Foreign Application Priority Data Oct. 1, 1970 Germany P 20 48323.3

52 us. 01. 280/112 A, 280/124 F 51 int. 01..., B603 17/04 58 Field ofSearch 280/112 A, 112 R,

[5 6] References Cited UNITED STATES PATENTS 4 3,550,993 12/1970 Peiffer280/124 F X Aug. 14, 1973 2,965,388 12/1960 Dettwiler 280/1 12 A2,165,617 7/1939 Paes 280/6 H 3,233,909 2/1966 Boone 280/6 H PrimaryExaminer-Philip Goodman Attorney-Craig, Antonelli & Hill 1571 ABSTRACTAn installation for stabilizing the vehicle body against curve-tilting,in which an erecting force is exerted on the side of the vehicle bodydisposed on the outside of the curve, whereby a pressure medium issupplied in dependence on the curve drive of the vehicle directly to thepistons of cylinder-piston units connected between the wheels and thevehicle body in such a mannet that the cylinder-piston unit associatedwith the wheel on the inside of the curve is shortened in the I sense ofa lowering of the vehicle body and the cylinder-piston unit associatedwith the wheel on the outside of the curve is lengthened in the sense ofa lifting of the vehicle body.

20 Claims, 1 Drawing Figure PATENIEDAUG 14 ms 3752.497

INSTALLATION FOR STABILIZING THE VEHICLE BODY AGAINST CURVE-TILTING Thepresent invention relates to an installation for stabilizing the vehiclebody against curve-tilting, in which an erecting force is exerted on thecurve-outerside of the vehicle body, especially with the use ofhydro-pneumatic springs for the vehicle spring system.

It is known to exert such an erecting force by means of a rotatingvane-type adjusting motor which acts on the wheel guide elements of anaxle by way ofa torsion rod stabilizer. The rotary vane-type adjustingmotor is thereby fed with a pressure medium in the one or the otherdirection of rotation from the pressure reservoir by way of a controlvalve controlled by the curve tilting. This known installation, however,presupposes a torsion rod stabilizer, which cannot be installedeverywhere.

The present invention aims at a simplification in the construction ofthe stabilization of the vehicle body, whereby the stabilizationincludes also such an influencing of the spring system and/or of thevehicle body, by means of which the body is tilted toward the insideopposite the centrifugal force in dependence on the curve drive of thevehicle. Accordingly, the present invention essentially consists in thata pressure medium is fed in dependence on the curve drive directly tothe pistons of cylinder-piston aggregates interconnected between thewheels and the vehicle body, especially hydro-pneumatic springs, in sucha manner that the cylinder-piston aggregate coordinated to the wheel onthe inside of the curve is reduced in the sense of lowering the vehiclebody and the cylinder piston aggregate coordinated to the wheel on theoutside of the curve is elongated in the sense of lifting the vehiclebody.

Preferably a double-acting displacement-piston aggregate adjusted independence on the curve drive is provided for the supply of the pressuremedium, whereby each piston of the piston aggregate acting asdisplacement space is connected crossed-over with an upper piston spaceof the cylinder-piston aggregate of one vehicle side and with a lowerpiston space of the cylinder-piston aggregate of the other vehicle side.

Advantageously, the piston of the cylinder-piston aggregateinterconnected between wheel and vehicle body and coordinated to thespring system is operatively connected by means of a piston rod with thewheel or with a part connected with the wheel or swinging in unisontherewith and the cylinder is operatively connected with the vehiclebody or with a part connected with the same. The diameter of the pistonsas well as of the piston rod thereby determine the ratio of theunidirectional spring. stiffness to the alternate spring stiffness.

Preferably a common working-displacement aggregate adjustable independence on the curve drive is provided for the spring systems of thefront and of the rear axle. In a particularly preferred embodiment, thecommon working-displacement aggregate is thereby provided with a centralworking cylinder-piston aggregate controlled by a pressure medium, whosepiston alternately acted upon depending on the curve drive connected bymeans of oppositely directed piston rods with one double-actingdisplacement-piston each for the front axle and the rear axle,respectively. The center piston thereby has advantageously a largerdiameter than the lateral double-acting pistons for the front and rearaxle.

The control valve controlling the displacement pistons, for example, byway of the center working piston is, in its turn, advantageouslycontrolled electrically. An accurate and particularly advantageouscontrol of the stabilization installation is achieved, which can beinstalled in the vehicle at any desired place, by means of a signalderived from the inclination of the vehicle body or the travel of aworking or displacement pistonsas measured by a displacement pick-up-andby means of a second signal derived from an acceleration pick-up, whichare compared in an electronic control device of conventionalconstruction.

Accordingly, it is an object of the present invention to provide aninstallation for the stabilization of the vehicle body againstcurve-tilting which avoids by simple means the aforementionedshortcomings and drawbacks.

Another object of the present invention resides in an installation forstabilizing the vehicle body against curve-tilting which can beinstalled into any vehicle and does not require, as a prerequisite, atorsion rod stabilizer or the like.

A further object of the present invention resides in an installation forstabilizing the vehicle body against curve-tilting which is simple inconstruction and reliable in operation and which utilizes existing partsin an effective manner.

These and further objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with thepresent invention, and wherein:

The single FIGURE is a schematic view of an installation in accordancewith the present invention for stabilizing the vehicle body againstcurve-tilting.

Referring now to the single FIGURE of the drawing, the cylinder-pistonaggregates (spring legs) of the front wheels coordinated to the springsystem are generally designated in this FlGURE by reference numerals 10aand 10b and the cylinder-piston aggregates of the rear wheelscoordinated to the spring system are designated generally by referencenumerals 11a and 11b, whereby the driving direction is indicated byarrow F. The pistons 12a, 12b and 13a, 13b are connected by means of thepiston rods 14a, 14b and 15a, 15b to a respective vehicle axle whereasthe cylinder 16a, 16b and 17a, 17b are connected to the vehicle bodypreferably under interconnection of damping means 18a, 18b and 19a, 19bof conventional construction, and more particularly are connectedhydraulically to the spring reservoirs 20a, 20b and 21a, 21b, which arein communication with the upper piston space 22a, 22b and 23 a, 23b. Thelower piston spaces 24a, 24b and 25a, 25b, as also additionally theupper piston spaces, are connected with the hydraulic system of thestabilization installation in the manner to be described more fullyhereinafter. By reason of the piston rods 14a, 14b and 15a, 15b thelower piston spaces have a smaller effective pressure area than theupper piston spaces.

The working-displacement aggregate for the adjustment of thecylinder-piston units 10a, 10b, 11a and 11b includes a cylinder 26 ofrelatively large diameter with a working piston 27 as well as twolateral displacement cylinders 28 and 29 of smaller diameter withdisplacement pistons 30 and 31 sliding therein, which are rig idlyconnected with the working piston 27 by piston rods. Piston spaces 32and 33 are formed in the working cylinder 26 on both sides of theworking piston 27, and piston spaces 34a, 34b and 35a, 35b are formed inthe displacement cylinders 28 and 29 on both sides of the pistons 30 and31, respectively.

The piston spaces 32 and 33 are alternately and seof the piston space35b into the piston spaces 23b and lectively fed with a pressure mediumfrom a pressure reservoir 39 by way of lines 36 and 37 by acorresponding control of a conventional control valve 38, which pressuremedium is appropriately the same pressure medium, especially oil, asalso fills the piston spaces of the cylinder-piston aggregates a, 10b,11a, 11b coordinated to the spring system as well as the piston spacesof the displacement cylinders 28, 29. The control valve 38 is controlledduring a curve drive by way of a conventional control device 51 by meansof lateral acceleration pick-up or transmitter 40 also of any knownconventional construction. The control device 51 can also be influencedin dependence on the steering or in any other appropriate known mannerin dependence of the curve drive.

As further illustrated in the drawing, the piston space 34a of thedisplacement cylinder 28 is connected by way of lines 41 and 42 with thepiston spaces 24a and 22b, the piston space 34b is connected by way oflines 43 and 44 with the piston spaces 22a and 24b, the piston space 35ais connected by way of lines 45 and 46 with the piston spaces 23a and band the piston space 35b is connected by way of lines 47 and 48 with thepiston spaces 25a and 23b so that always a lower piston space of thecylinder-piston aggregate coordinated to the spring system of one wheelofa vehicle axle is connected with the upper piston space of thecylinderpiston aggregate coordinated to the spring system of theopposite wheel as well as with one of the piston spaces of adisplacement cylinder of the workingdisplacement aggregate.

The drawing further indicates a line 50 (shown in dash lines) controlledby a motion pick-up 49 of conventional construction and starting fromthe cylinder 26 of the operating aggregate, which leads to theelectronic control device 51 in which the displacement of the workingpiston 27 as measured by the motion pickup 49 or the tilting of thevehicle body is compared with a signal produced by the lateralacceleration transmitter 40 for purposes of controlling the pressuremedium supply to the cylinder 26.

OPERATION The operation of the stabilization installation according tothe present invention is as follows:

If the vehicle drives, for example, through a left curve, then thecontrol valve 38 receives from the control device 51 a signal andpermits the pressure medium, for example, pressure oil, to reach thepiston space 33 from a pressure reservoir 39 by way of the line 37 andto act on the work-piston 27. The latter is displaced in the directionof arrow X, together with the displacement pistons and 31 so that thepressure medium is sucked out of the piston spaces 22a, 24b by way ofthe lines 44, 43 into the piston space 34b and out of the piston spaces23a, 25b by way of lines 46, 45 into the piston space a and pressuremedium is displaced out of the piston space 340 into the piston spaces24a and 22b by way of lines 41 and 42 and out gregates, i.e., the springlegs 10 a, lla, coordinated to the spring system of the left vehicleside and corresponding to the inner side of the curve, are therebyshortened or acted upon in a shortening sense whereas thecylinder-piston aggregates, i.e., the spring legs 10b,

11b coordinated to the spring system of the right vehicle side andcorresponding to the outside of the curve are elongated or acted upon inan elongating sense. If the working piston has travelled the pathassociated with the effective lateral actuation or if the vehicle bodyhas reached the corresponding inclination, then the signal of thecontrol device 51 disappears and the oil supply to the space 33 stops.Since the control device 51 and its operation are known as such andinvolve conventional circuits, a detailed description thereof isdispensed with herein. In this manner the effects of the centrifugalforces on the vehicle body can be compensated for either completely orpartially and the vehicle body can be stabilized against curve-tiltingor can be tilted toward the inside of the curve.

It is thereby possible by the electronic control device 51 to coordinateto each magnitude of the lateral acceleration a predetermined path ofthe working piston 26 and therewith a predetermined stiffening of thespring system or a predetermined inward tilting of the vehicle body.

While we have shown and described only one embodiment in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to those skilled in the art and we, therefore, do not wish to belimited to the details shown and described herein but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

What we claim is:

1. An installation for stabilization of curve tilting of a vehicle bodyprovided with front and rear wheels comprising double-actingcylinder-piston units interconnected between the wheels and the vehiclebody, a common displacement unit for supplying a pressure medium independence upon the curve direction of the vehicle, means connected to afirst portion of said displacement unit for supplying the pressuremedium to the front wheels, means connected to a second portion of saiddisplacement unit for supplying the pressure medium to the rear wheelsof the vehicle and crossover means for supplying the pressure mediumfrom the upper side of a cylinder-piston unit on one vehicle side withthe lower side of a cylinder-piston unit on the other vehicle side.

2. An installation according to claim 1, characterized in that saidcylinder-piston units include hydropneumatic spring means.

3. An installation according to claim 2, wherein the piston of acylinder-piston unit is connected to the wheel by means ofa piston rodand the cylinder thereof is connected with the vehicle body.

4. An installation according to claim 3, characterized in that thecommon displacement unit includes a central working cylinder-piston unitcontrolled by a pressure medium whose piston, alternately acted upondepending on the curve drive, is operatively connected by means ofoppositely directed piston rods with one double-acting displacementpiston each for the front wheels and the rear wheels, respectively.

5. An installation according to claim 4, characterized in that thecentral working piston has a larger effective diameter than the lateraldouble-acting displacement pistons.

6. An installation according to claim 5, further comprising a controlvalve means for supplying the working cylinder piston unit with thepressure medium and for adjusting the cylinder-piston units, saidcontrol valve means being controlled by an electronic control means forproviding a signal of the curve path of the vehicle.

7. An installation according to claim 6, characterized in that theinclination of the vehicle body is measured and together with thelateral acceleration, measured by an acceleration measuring means, isprocessed in an electronic control means into a signal which controlsthe control valve means in a predetermined manner.

8. An installation according to claim 7, characterized in that thetilting of the vehicle body is measured by measuring the travel of oneof the pistons consisting of working and displacement pistons.

9. An installation according to claim 8, characterized in that saidcylinder-piston units include hydropneumatic spring means.

10. An installation according to claim 1, wherein the piston of acylinder-piston unit is connected to the wheel by means ofa piston rodand the cylinder thereof is connected with the vehicle body.

11. An installation according to claim 1, characterized in that thecommon displacement unit includes a central working cylinder-piston unitcontrolled by a pressure medium whose piston, alternately acted upondepending on the curve drive, is operatively connected by means ofoppositely directed piston rods with one double-acting displacementpiston each for the front wheels and the rear wheels, respectively.

12. An installation according to claim 11, characterized in that thecentral working piston has a larger effective diameter than the lateraldouble-acting displacement pistons.

13. An installation according to claim I, further comprising a controlvalve means for supplying said common displacement unit with thepressure medium and for adjusting the cylinder-piston units said controlvalve means being controlled by an electronic control means forproviding a signal of the curve path of the vehicle.

14. An installation according to claim 13, characterized in that theinclination of the vehicle body is measured and together with thelateral acceleration, measured by an acceleration measuring means, isprocessed in an electronic control means into a signal which controlsthe control valve means in a predetermined manner.

15. An installation according to claim 14, characterized in that thetilting of the vehicle body is measured by measuring th travel of one ofthe pistons consisting of working and displacement pistons.

16, An installation according to claim 1 wherein said commondisplacement unit includes a main cylinder having disposed therein aworking piston, said working piston being provided with a piston rod oneach side thereof extending into said first and second portions of saiddisplacement unit.

17. An installation according to claim 16, wherein said first and secondportions of said displacement unit include a first and second cylinder,each disposed on one side of said main cylinder, having a pistonconnected to said piston rods on said working piston.

18. An installation according to claim 17 wherein said first and secondcylinders are divided into a first and second chambers by the pistondisposed therein with said means for supplying the pressure medium tothe front wheels and said means for supplying the pressure medium to therear wheels being in communication with said first and second chambers.

19. An installation according to claim 18 wherein said means forsupplying the pressure medium to the front and rear wheels each includea first and second conduit communicating respectively with said firstand second chambers.

20. An installation according to claim 19 wherein said first and secondconduits are operatively connected to the lower side of a respectivedouble-acting cylinder-piston unit.

1. An installation for stabilization of curve tilting of a vehicle bodyprovided with front and rear wheels comprising double-actingcylinder-piston units interconnected between the wheels and the vehiclebody, a common displacement unit for supplying a pressure medium independence upon the curve direction of the vehicle, means connected to afirst portion of said displacement unit for supplying the pressuremedium to the front wheels, means connected to a second portion of saiddisplacement unit for supplying the pressure medium to the rear wheelsof the vehicle and cross-over means for supplying the pressure mediumfrom the upper side of a cylinder-piston unit on one vehicle side withthe lower side of a cylinder-piston unit on the other vehicle side. 2.An installation according to claim 1, characterized in that saidcylinder-piston units include hydropneumatic spring means.
 3. Aninstallation according to claim 2, wherein the piston of acylinder-piston unit is connected to the wheel by means of a piston rodand the cylinder thereof is connected with the vehicle body.
 4. Aninstallation according to claim 3, characterized in that the commondisplacement unit includes a central working cylinder-piston unitcontrolled by a pressure medium whose piston, alternately acted upondepending on the curve drive, is operatively connected by means ofoppositely directed piston rods with one double-acting displacementpiston each for the front wheels and the rear wheels, respectively. 5.An installation according to claim 4, characterized in that the centralworking piston has a larger effective diameter than the lateraldouble-acting displacement pistons.
 6. An installation according toclaim 5, further comprising a control valve means for supplying theworking cylinder piston unit with the pressure medium and for adjustingthe cylinder-piston units, said control valve means being controlled byan electronic control means for providing a signal of the curve path ofthe vehicle.
 7. An installation according to claim 6, characterized inthat the inclination of the vehicle body is measured and together withthe lateral acceleration, measured by an acceleration measuring means,is processed in an electronic control means into a signal which controlsthe control valve means in a predetermined manner.
 8. An installationaccording to claim 7, characterized in that the tilting of the vehiclebody is measured by measuring the travel of one of the pistonsconsisting of working and displacement pistons.
 9. An installationaccording to claim 8, characterized in that said cylinder-piston unitsinclude hydropneumatic spring means.
 10. An installation according toclaim 1, wherein the piston of a cylinder-piston unit is connected tothe wheel by means of a piston rod and the cylinder thereof is connectedwith the vehicle body.
 11. An installation according to claim 1,characterized in that the common displacement unit includes a centralworking cylinder-piston unit controlled by a pressure medium whosepiston, alternately acted upon depending on the curve drive, isoperatively connected by means of oppositely directed piston rods withone double-acting displacement piston each for the front wheels and therear wheels, respectively.
 12. An installation according to claim 11,characterized in that the central working piston has a larger effectivediameter than the lateral double-acting displacement pistons.
 13. Aninstallation according to claim 1, further comprising a control valvemeans for supplying said common displacement unit with the pressuremedium and for adjusting the cylinder-piston units said control valvemeans being controlled by an electronic control means for providing asignal of the curve path of the vehicle.
 14. An installation accordingto claim 13, characterized in that the inclination of the vehicle bodyis measured and together with the lateral acceleration, measured by anacceleration measuring means, is processed in an electronic controlmeans into a signal which controls the control valve means in apredetermined manner.
 15. An installation according to claim 14,characterized in that the tilting of the vehicle body is measured bymeasuring th travel of one of the pistons consisting of working anddisplacement pistons.
 16. An installation according to claim 1 whereinsaid common displacement unit includes a main cylinder having disposedtherein a working piston, said working piston being provided with apiston rod on each side thereof extending into said first and secondportions of said displacement unit.
 17. An installation according toclaim 16, wherein said first and second portions of said displacementunit include a first and second cylinder, each disposed on one side ofsaid main cylinder, having a piston connected to said piston rods onsaid working piston.
 18. An installation according to claim 17 whereinsaid first and second cylinders are divided into a first and secondchambers by the piston disposed therein with said means for supplyingthe pressure medium to the front wheels and said means for supplying thepressure medium to the rear wheels being in communication with saidfirst and second chambers.
 19. An installation according to claim 18wherein said means for supplying the pressure medium to the front andrear wheels each include a first and second conduit communicatingrespectively with said first and second chambers.
 20. An installationaccording to claim 19 wherein said first and second conduits areoperatively connected to the lower side of a respective double-actingcylinder-piston unit.